In-situ HIC growth monitoring probe

ABSTRACT

The present application concerns in-situ intrusive probe systems and methods. The probe systems described herein can be installed flush to a hydrocarbon containing structure, such as a pipeline, vessel, or other piping system carrying crude, gas or sour products. The probe systems include hydrogen induced cracking (HIC)-resistant microstructure such that as atomic hydrogen permeates the probe surface, the probe captures recombined hydrogen gas. The pressure of the resultant hydrogen gas buildup is measured and predictions as to the HIC activity of that area can be made.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/879,941, filed Jan. 25, 2018, which is based on and claims priorityto U.S. Provisional Patent Application 62/452,464, filed Jan. 31, 2017,the entire contents of which are incorporated by reference herein as ifexpressly set forth in their respective entireties herein.

FIELD OF THE INVENTION

The present invention generally relates to assessing asset damage tometal structures. More particularly, the present invention relates toprobe systems for assessment of hydrogen-induced damage to metalpipelines.

BACKGROUND OF THE INVENTION

Hydrogen-induced cracking (HIC) is a persistent problem for metal (e.g.,steel) structures, such as pipelines, pressure vessels, and other pipingsystems, and particularly those that are composed of non-HIC resistantsteel and service hydrocarbon products (e.g., sour gas or natural gas).Naturally occurring acid gases in hydrocarbon products, such as CO₂ andH₂S, dissolve in the water phase of the hydrocarbon liquid product. Theelectrochemical reactions associated with these processes yield atomichydrogen, which is adsorbed onto the corroding internal wall surfaces ofthe asset. The majority of this adsorbed atomic hydrogen recombines ontothe steel surfaces, forming molecular hydrogen (hydrogen gas), and“bubbles off” with no damage to the steel. However, in the presence ofH₂S, a certain portion of the adsorbed atomic hydrogen does notrecombine into hydrogen gas, but instead permeates through the steelsurface, diffuses through the metallic lattice and eventually recombinesinside “voids” within the metal wall thickness. These voids areassociated with metallurgical defects formed during the steel makingprocess (typically Manganese sulfide (MnS) non-metallic inclusions). Thepressure resulting from the hydrogen gas generated inside these voidscan reach very high values (up to 12,000 bars, i.e., 1,200 MPa in theabsence of passivation of the steel surfaces). These very high pressurescontribute to the local reduction in cohesive forces at the tip ofnon-metallic inclusions (hydrogen embrittlement), and ultimately lead toblisters, crack initiation and subsequent growth of HIC. HIC cracks canalso lead to the more critical through-thickness cracking termedStep-Wise Cracking (SWC). Blisters and cracks associated with HIC andSWC can grow over time and result in the failure of a metal pipeline.

Integrity engineers manage HIC-induced degradation and maintainstructure integrity by performing regular inspection of pipelines toidentify and monitor HIC-affected areas. For example, integrityengineers perform In-Line Inspection (ILI) of pipelines to identify HICclusters that are thereafter excavated for closer inspection by AdvancedUltrasonic Testing (AUT). AUT is conducted to validate ILI results,determine the remaining wall thickness of the pipeline, and also tocheck for the presence of SWC (which cannot be detected usingconventional ILI techniques, such as magnetic flux leakage andconventional ultrasonic testing). These results are then analyzed usingindustry standard codes for fitness-for-service (FFS)—(such as API-579or ASME B31G) and an integrity decision is made. AUT examinations arecarried out on high severity locations to obtain the data required forthe assessment. Based on the outcome of the assessment, AUT examinationsare carried out more frequently with the frequency in part typicallydepending upon inspection for linear HIC or step-wise cracking (SWC).However, this approach is not feasible for pipelines due to theimpracticality and cost-ineffectiveness of conducting frequent AUTexaminations (e.g., semi-annually) for buried transmission pipelines andto the difficulty of prioritizing of multiple affected line sections onthe same line. Furthermore, AUT examinations lack a way to identify andprioritize inspection of highly active HIC active areas that may emergein between inspections.

Moreover, conventional in-situ systems practice electrochemical methods,pressure-based methods, and vacuum-based probe methods that calculatecorrosion rates indirectly from measured permeating gas rates and thusare non-intrusive to the pipeline. Non-intrusive electrochemical methodsand probes, as well as pressure-based and vacuum-based probes, havelimited sensitivity for measuring hydrogen as they can only measurehydrogen buildup that passes from the structure's internal surface tothe structure's external surface. Most hydrogen that diffuses from theinside wall of a structure does not diffuse completely through thestructure to its external surface, but rather the hydrogen is entrappedinside the wall thickness. This limitation underestimates the amount ofhydrogen generated and the actual pressure can be much higher andtherefore can lead to miscalculated corrosion rates since the corrosionrates are based on the measurement of hydrogen buildup. Further, suchprobes are not practical for buried lines and can include measurementchemicals that are impracticable for intrusive field application inregard to chemical liquids in present in assets.

As such, there exists a need to provide warning systems that identifieshydrogen pressure buildup active areas and to prioritize AUTexaminations to inspect the most HIC active areas of a metal structurefirst. There further exists a need for an intrusive in-situ monitoringprobes. It is in regard to these issues and others that the presentinvention is provided.

SUMMARY OF THE INVENTION

Throughout the specification, terms may have nuanced meanings suggestedor implied in context beyond an explicitly stated meaning. Likewise, thephrase “in one embodiment” as used herein does not necessarily refer tothe same embodiment and the phrase “in another embodiment” as usedherein does not necessarily refer to a different embodiment. Similarly,the phrase “one or more embodiments” as used herein does not necessarilyrefer to the same embodiment and the phrase “at least one embodiment” asused herein does not necessarily refer to a different embodiment. Theintention is, for example, that claimed subject matter includescombinations of example embodiments in whole or in part.

The present disclosure details intrusive warning probe systems andmethods for installation at an oil or gas structure surface (e.g., asteel pipeline) in order to monitor and measure hydrogen pressurebuildup. To install the probe system, a hole is bored through thepipeline surface and a coupling mount having a threaded inner surface isseated in the hole. The probe system is then screwed into the couplingmount via an access fitting. Specifically, probe installation isarranged such that an exposed surface of the probe is positioned atleast substantially flush to the inner surface of the structure (i.e.,“flush geometry”). The exposed probe surface is made of the samematerial grade as the structure surface to ensure that the samecorrosion and hydrogen induced cracking (HIC) processes take place atboth the probe and the oil/gas structure, though unlike the structuresurface, the exposed probe surface is metallurgically modified to haveHIC-resistant microstructure. In this way, diffusing hydrogen can enterthe probe system, but will not become trapped in metallurgical cavitiesinside the exposed probe surface.

The probe system includes a HIC-simulation cavity (collection cavity orinternal cavity) in which diffusing atomic hydrogen (H) permeates to andrecombines within the cavity to form hydrogen gas (H₂). To ensure thatall permeating atomic hydrogen remains in the cavity and does not escapeback into the oil/gas structure, one or more surfaces of the cavityinclude atomic hydrogen diffusion barrier. As hydrogen gas content inthe cavity increases, the pressure in the cavity increasescorrespondingly, mimicking the HIC process. The system monitors thecavity pressure with a hydrogen sensor (e.g., digital hydrogen gauge,transducer, etc.) and determines corresponding hydrogen build-up rates.High hydrogen build-up rates indicate an increased chance of HIC orstep-wise cracking (SWC), thereby providing a warning system as to whichstructure areas likely need engineer inspection. Additionally, thesimulation cavity is advantageously designed to have a significantlysmaller volume than commercially available probes, which provides highermonitoring sensitivity to pressure build-ups.

In one aspect, provided herein are probe systems that comprise a probebody that has an access end and a base end. At the access end, anexposed surface is exposed to a corrodent. At the base end is a capthreaded to interlockingly engage with the base end of the probe body.In one or more embodiments, the probe body has a solid first end portiondefined by the exposed surface configured to be exposed to the corrodentlocated within the metal asset. The probe body has an internal openingthat terminates at a location spaced from the exposed surface. Aninsert, such as a filler rod, is disposed within the internal opening(blind hole) of the probe so as to define a collection cavity definedbetween the insert and an inner wall of the probe body. In one or moreembodiments, a diffusion barrier is disposed along the inner wall of theprobe body and is formed of a material that is at substantiallyimpermeable to a gas generated in the collection cavity by the corrodentso as to prevent passage of the gas from the collection cavity to thesurrounding inner wall of the probe body. A conduit is in fluidcommunication with the collection cavity for receiving the gas generatedby the corrodent. In one or more embodiments, a pressure measuringdevice is coupled to the conduit for measuring a pressure of the gascreated by the corrodent. For example, the pressure measuring device canbe a pressure gauge or transducer.

In another aspect, provided herein are probe systems that comprise aprobe body that has an access end and a base end. At the access end, anexposed surface is exposed to a corrodent. At the base end is a capthreaded to interlockingly engage with the base end of the probe body.In one or more embodiments, the probe has a probe body including anaccess end portion with an exposed surface configured to be exposed to acorrodent located within the metal asset. The access end portion has arecessed portion formed opposite the exposed surface. An insert has anaccess end and a base end, with the access end being disposed adjacentrecessed portion of the probe body so as to define a collection cavitythat is fluid-tight and configured to collect the corrodent thatpermeates through the exposed surface of the probe body, whereby a gasis generated in the collection cavity by the corrodent. The insertincludes a through hole that passes therethrough and is open at both theaccess end and the base end such that the through hole is in fluidcommunication with the collection cavity.

In one or more embodiments, a pressure measuring device is coupled tothe conduit for measuring a pressure of the gas created by thecorrodent. For example, the pressure measuring device can be a pressuregauge or transducer.

Provided herein are methods for warning for hydrogen induced cracking(HIC). The method includes inserting an intrusive probe system into ametal structure that is at least substantially flush to the inner wallof the metal structure. The intrusive probe system is as describedherein. Next, atomic hydrogen is allowed to permeate the exposed surfaceof the probe system. Thereafter, molecular hydrogen is generated in theinternal cavity of the probe system. The pressure of the molecularhydrogen is then measured. The method then determines whether themeasured pressure identifies a risk of hydrogen induced cracking.Finally, the method schedules advanced ultrasonic testing according tothe risk of hydrogen induced cracking.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the figures of the accompanying drawingswhich are meant to be exemplary and not limiting, in which likereferences are intended to refer to like or corresponding parts, and inwhich:

FIG. 1A illustrates an intrusive probe system according to one or moreembodiments of the present invention;

FIG. 1B is a greatly magnified view of a portion of the intrusive probesystem of FIG. 1 showing an internal cavity that can have a width ofbetween about 10 microns and 50 microns in one embodiment;

FIG. 2A illustrates the intrusive probe system of FIG. 1 as mounted intoan oil or gas structure;

FIG. 2B illustrates the intrusive probe system of FIG. 1 as mounted intoan oil or gas structure and configured to be flush to the inner surfaceof the structure;

FIG. 3 illustrates the generation of atomic hydrogen and recombinationof hydrogen gas within a cavity of an intrusive probe system accordingto one or more embodiments of the present invention;

FIG. 4 illustrates an alternative intrusive probe system according toone or more embodiments of the present invention; and

FIG. 5 illustrates the alternative intrusive probe system of FIG. 4 asmounted into an oil or gas structure and configured to be flush to theinner surface of the structure.

DETAILED DESCRIPTION OF THE INVENTION

As described herein, a “structure” can include oil or gas pipelines,other containers, or metal assets. For example, the probe systemsdescribed herein can be implemented at a steel pipeline structure.

Provided herein are in-situ intrusive probe systems and methods thatmimic voids associated with HIC cracks in steel structures, such aspipelines, pressure vessels, and piping systems. The intrusive probesystems simulate hydrogen pressure build-up occurring from therecombination of atomic hydrogen generated from corrosion processescaused by transported hydrocarbon products (crude, gas, or sourdisposable waters) in pre-existing HIC cracks detected during AdvancedUltrasonic Testing (AUT) or In-Line Inspection (ILI) inspections.Specifically, the probe systems described herein couple to the outersurface of the structure and provide a probe hydrogen entry surface thatis at least substantially flush with the internal surface of thestructure. An at least substantially flush geometry ensures that theexposed entry surface of the probe is liquid tight to the internal wallof the structure such that the probe experiences the same fluid flowcharacteristics (e.g., fluid velocity, shear stress, local water contentand chemistry) as the rest of the structure internal wall, and further,the flush geometry ensures that internal inspection procedures and/orcleaning procedures are not impeded.

The in-situ, or “at the site,” measuring and monitoring of hydrogenpressure build up as performed by the intrusive probe systems andmethods described herein includes the following steps in one or moreembodiments: (1) reviewing existing ILI maps for the structure (e.g., anoil or gas pipeline) of interest, and identifying locations of HICclusters or locations of maximum corrosion rates; (2) boring an accesspoint in the structure wall within the vicinity of these identifiedlocations; (3) mounting a coupling mount at the access point; (4)threading the probe system through an access fitting and screwing theaccess fitting to the coupling mount until the probe surface is flushwith in the internal surface of the structure; (5) monitoring of thehydrogen pressure build up at the probe system with a pressure sensingdevice (e.g., digital hydrogen gauge, transducer, etc.) as atomichydrogen permeates the probe system and recombines to hydrogen within acavity in the probe; and (6) performing AUT examinations at the most HICactive areas on priority basis (i.e., areas that show highest hydrogenpressure build rates). AUT examinations can be prioritized becausemeasured hydrogen pressure data is correlated with HIC growth rate asestablished from first principles equations or determined fromexperimental work and/or extensive field experience (i.e., empiricalcorrelation between pressure build-up rate and HIC growth ratedetermined from successive ILI runs). The hydrogen pressure data iscollected via real-time online monitoring or off-line monitoring, suchas with a data logger. In one or more embodiments, the probe systemsdescribed herein include a wireless communication system as is known inthe art to communicate between the probe system and a remote controlarea.

In this way, the intrusive probe systems and methods described hereinoptimize inspection resources by optimizing and prioritizing excavationdigs and AUT inspections, monitor process upsets, provide a mechanismfor studying the effect of added chemicals (e.g., DRA, inhibitors) onhydrogen permeation through steel. Further, the data collected can beused to build more accurate HIC/SWC prediction models.

With reference now to FIG. 1 , an intrusive probe system 100 accordingto one or more embodiments is provided. The probe 100 includes a probebody 105 having an access end 107 and a base end 109 that is configuredto be positioned such that the access end 107 is flush to a metalstructure (e.g., structure 205 of FIG. 2A) and exposed to the liquids orgas in which atomic hydrogen is produced. As shown in the FIG. 1 , probebody 105 can be formed so as to have an opening (bore) formed therein soas to define an internal cavity, with the access end 107 being theclosed end of the probe body 105, while the base end 109 is an open endin which the opening in the probe body 105 is accessible.

The access end 107 of the probe body 105 includes an exposed (outer)surface 110. The exposed surface 110 is made of the same metal (e.g.,steel) grade as the structure to be monitored, but has a HIC-resistantmicrostructure. This arrangement permits atomic hydrogen to pass intothe probe 100, as described below, to form hydrogen gas by the samemechanism and same rates as in the surrounding structure, but theHIC-resistant microstructure of the access end 107 prevents hydrogen gasfrom becoming entrapped in metallurgical cavities. In other words, inthe closed end (access end 107), there is no formation of molecularhydrogen and instead the atomic hydrogen is free to pass through thismaterial to a cavity (which mimics voids associated with HIC cracks) asdescribed below. It will be appreciated that molecular hydrogen stillforms along the exposed surface of the access end 107 and bubbles off,but the permeating portion of hydrogen does not get entrapped inside thebody the access end 107 due to the access end 107 being made of aHIC-resistant steel which has no metallurgical defects that entraphydrogen. Further, the HIC-resistant microstructure (of the probe body105) militates against the development of HIC/SWC cracks within theprobe system 100 itself. In one or more embodiments, the access end 107of the probe 100 includes one or more O-rings 115. The O-rings 115 arearranged about the outer surface of the probe body 105 adjacent to theaccess end 107 to ensure liquid-tight geometry such that no liquidenters between the probe and structure wall.

As mentioned above, the probe body 105 includes an internal cavity 129(hollow space) (See, FIG. 1B) to collect diffused hydrogen gas that haspasses through the access end 107 of the probe 100. The internal cavity129 is defined, at least in part, by the closed ended opening, formed inthe body 105 and in one or more embodiments, the internal cavity 129 isalso defined by a filler rod (an insert) 120 that is inserted into theopening formed in the probe body 105. In other words, the internalcavity 129 is formed between the filler rod 120 and the inner wall ofthe hollow probe body 105 as best shown in FIG. 1B. The filler rod 120has a first (access) end and a second or (base end) end is inserted inthe internal cavity, thereby creating and defining the internal cavity129 that receives the atomic hydrogen from the access (closed) end 107.It will be appreciated that the cavity 129 is the result of the tightfit of the filler rod into the bore. The tight fit will leave an annuli(the space of the annuli will be determined by surface roughness of thefiller rod 120 and the surface roughness of the inner wall of the hollowprobe body 105. It will be appreciated that width of the annuli space(cavity 129) can be approximately 10 microns to 50 microns. However, itwill be appreciated that these values are not limiting and it is withinthe scope of the present invention that dimensions outside of this rangecan equally be possible. The internal cavity 129 terminates in aninternal end wall 125 that is proximate but spaced from the exposedsurface 110 as shown in FIG. 1A.

In the exemplary embodiment as shown in FIG. 1 , the filler rod 120extends longitudinally from the base end of the probe body 105 towardthe access end 107. The first end of the filler rod 120 is thusidentified as the end nearer to the access end 107 of the probe body105, and the second end of the filler rod 120 is identified as the endnearer to the base end 109 of the probe body 105.

The first end of the filler rod 120 can be placed into abuttingrelationship (i.e., in intimate contact) with the access end 107 of theprobe body 105, thereby defining the internal cavity 129 (for hydrogencollection) as being between an outer surface of the side wall of thefiller rod 120 and the inner wall of the probe body 105 that defines theopening formed in the probe body 105. In the embodiment in which thefiller rod 120 has a cylindrical shape and the opening in the probe body105 has a circular shape, the internal cavity 129 has an annular (ring)shape. One end of the annular shaped cavity 129 abuts the access end 107of the probe body 105 and therefore the atomic hydrogen that passesthrough the access end 107 enters into the annular shaped cavity 129 atthis end. As described below, the filler rod 120 is formed of a materialthat is not conductive to hydrogen diffusivity and therefore, the atomichydrogen cannot migrate into the filler rod 120 from the access end 107of the probe body 105. Instead, the atomic hydrogen is channeled intothe annular shaped cavity that surrounds the filler rod 120. The firstend of the filler rod 120 can be joined to the access end 107 (i.e., theend wall defining the opening formed in the probe body 105) using anynumber of conventional techniques.

It will be appreciated that the size of the opening (bore) formed in theprobe body 105 and the size of the filler rod 120 determines the size ofthe internal cavity 129 that receives the atomic hydrogen. Carefulcontrol over these parts allows one to create an internal space (annularshaped cavity) that provides increased sensitivity of the probe 100 formeasuring hydrogen gas buildup within the probe 100. Atomic hydrogenpresent in the oil or gas structure diffuses through the exposed surface110 to the annular shaped internal cavity 129 where it can recombine toform hydrogen gas (molecular hydrogen).

As mentioned above, in one or more embodiments, the filler rod 120 ismade of materials having low or no hydrogen diffusivity. For example,the filler rod 120 can be made of austenitic stainless steel or oxidizedcarbon steel or glass. The selection of this type of material for fillerrod 120 forces the atomic hydrogen that passes through the access end107 of the probe 100 to be directed to the annular shaped cavitysurrounding the filler rod 120 as opposed to passing into and throughthe filler rod 120 itself.

In one or more embodiments, the material between the end of the fillerrod 120 and the exposed surface 110 can be made of the same metallicgrade and have the same HIC-resistant microstructure as the exposedsurface. In other words, the access end 107 (i.e. the closed end of thebody 105) is formed of the same material that defines the exposedsurface 110 since exposed surface 110 in effect is an outer surface ofthe access end 107.

In one or more embodiments, a diffusion barrier 130 is provided andlocated within the annular shaped cavity to prevent hydrogen gascaptured by the probe body 105 (i.e., hydrogen gas located within theannular shaped cavity) from escaping to the surrounding environment(i.e., to the pipeline or external environment). More particularly, thediffusion barrier 130 can be formed along the inner side wall of theprobe body 105 that defines the opening formed therein and therefore,the annular shaped (hydrogen collection) cavity is formed between theside wall of the filler rod 120 and the diffusion barrier 130 (See, FIG.1B). Since, as mentioned above, the filler rod 120 is formed of amaterial that has low or no hydrogen diffusivity and therefore, incombination with the diffusion barrier 130, define a collection cavityin which both the inner and outer walls that define the collectioncavity 129 are designed to prevent the escape of hydrogen therethrough.

The diffusion barrier 130 can be formed of any number of suitablematerials so long as they prevent hydrogen diffusion and for example,can be an oxide layer (e.g., iron oxide) or other coating (e.g.,austenitic stainless steel layer, and a ceramic layer, such as Si₃N₄)that is formed along the cavity wall (i.e., outer cavity wall) byheat-treating the cavity in an oxygen-rich atmosphere. In this way, theamount of captured hydrogen can be reliably measured without atomichydrogen or the hydrogen gas diffusing into the surrounding structure(e.g., as by diffusing into the side wall of the body 105 that surroundsthe diffusion barrier 130).

With continued reference to FIG. 1 , a cap 135 is coupled to the baseend 109 of the probe body 105. In one or more embodiments, the cap 135is threaded to interlockingly engage with the base end 109 of the probebody 105. In other embodiments, the cap 135 is coupled to the probe body105 by other means, such as screws, adhesives, fasteners, or the like.The cap 135 can be made of any suitable materials, such as metal orplastic. An O-ring 137 can be provided to ensure a sealed fit betweenthe cap 135 and an adjacent, abutting structure as described below. Asshown in the figures, the collection cavity 129 is at least partiallydefined by the cap 135 since one end of the filler rod 120 is disposedwithin the cap 129 and the collection cavity 129 is formed about thefiller rod 120.

A conduit 140 is further coupled to the base end of the filler rod 120.The conduit 140 can be a channel, pipe or tube that is designed tocapture the hydrogen gas combined within the annular shaped cavity(collection cavity or chamber) (it will also be understood that someatomic hydrogen may combine in the conduit 140 to form hydrogen gas).The conduit 140 is further coupled to a pressure measuring device 145.The conduit 140 is in fluid communication with the annular shaped cavity129 such that the hydrogen gas in the annular shaped cavity 129 flowsinto the conduit 140 and then as the hydrogen gas passes through theconduit 140, the pressure measuring device 145 measures the pressurecaused by hydrogen build-up, which in turn provides an estimate of thehydrogen buildup in-situ at the structure (e.g., pipe wall). Thehydrogen gas will thus flow along the annular shaped cavity 129 andunderneath the bottom end of the filler rod 120 to access the conduit140. The pressure measuring device 145 can be a pressure gauge ortransducer or other suitable device.

With reference now to FIGS. 2A-B, the installation of probe system 100to a structure 205 is illustrated. The structure 205 can be a metal(e.g., steel) structure that transports hydrocarbon products, such as apipeline, pressure vessel, or other piping system transporting oil orgas. To couple the probe system 100 to the structure 205, the probesystem is first coupled to an access fitting 210. In one or moreembodiments, the access fitting 210 is a threaded metal or plasticcomponent that is sized and shaped to couple with the cap 135 or otherportion of probe body 105. In other embodiments, the access fitting 210is coupled to the probe body by screws, adhesives, fasteners, or thelike. The access fitting 210 and the cap 135 couple to form an air-tightseal to prevent any hydrogen gas from escaping. A hole is bored throughthe wall of structure 205 that is sized and shaped to receive the probesystem 100. In certain embodiments, a coupling mount 215 is secured atthe hole bored in structure 205 in order to receive the access fitting210. For example, the coupling mount 215 can be a threaded metal orplastic component that is sized and shaped to mate with the accessfitting 210.

As shown in FIG. 2A, the probe system 100 is secured within the accessfitting 210, the access fitting being coupled to the coupling mount 215such that an entry mouth 220 to the structure 205 is the same or similarsize as the exposed surface 110 of the probe system. Then, as shown inFIG. 2B, the probe system 100 is coupled in place such that the exposedsurface 110 is flush to the inner wall of structure 205. The probesystem 100 is considered to be “flush” if it is installed such that theexposed surface 110 does not extend substantially beyond the inner wallof the structure 205 and is not recessed relative to the inner wall ofthe structure 205 (e.g., it is less than about 1 mm from the inner wallof the structure 205. The probe system 100 is not considered to be flushif it is merely installed on the outer wall of the structure 205, as ina “patch probe.” Unlike patch probes, in which atomic hydrogenrecombines in the structure wall before ever reaching the patch probe,in the flush configuration, the probe system 100 captures diffusedatomic hydrogen at the boundary of the structure 205, which recombinesto molecular hydrogen in the cavity of the probe instead of in thestructure itself. This arrangement better mimics HIC generation andallows for increased and more accurate hydrogen flux measurement thanwith patch probes. Additionally, the flush arrangement of probe system100 provides advantages over fully intrusive probe types (i.e., in whichthe probe extends into the structure beyond the inner wall, typicallyinto the hydrocarbon product—for example, the Model 6400 hydrogen probemanufactured by Rohrback Cosasco), as in those types water accumulatesin a space between the probe and the structure surface, which changesthe local pH around the probe and affects corrosion rates and hydrogenpermeation rates. Thus, with fully intrusive probes, the measuredpressure build up does not reflect true hydrogen entry to the probe atthe structure section. Moreover, the flush geometry of probe system 100does not impede pipeline operations (e.g., cleaning and inspectionoperations), and does not allow liquid or gas to escape the structure205.

With reference now to FIG. 3 , the generation of atomic hydrogen andrecombination of hydrogen gas within a cavity of an intrusive probesystem according to one or more embodiments of the present invention isillustrated. For example, the probe system 100 could be installed atleast substantially flush to structure 205 as previously described. Thestructure 205 contains liquid or gas hydrocarbon products 305 in liquidor gas form that produce atomic hydrogen 310. Atomic hydrogen 310migrates to the inner surface of structure 205, where it permeates thesurface of the structure 205 and recombines into hydrogen gas. As shownin FIG. 3 , certain atomic hydrogen 310 permeates the exposed surface110 of the probe system 100 which, as mentioned, is installed in a flushorientation. As previously discussed, after passing through the accessend 107 of the probe body 105, the atomic hydrogen flows into thehydrogen collection cavity 129, described above, where it combines intohydrogen gas. The hydrogen gas continues to the conduit 140, where it iscollected and the pressure is measured by pressure measuring device 140.

With reference now to FIG. 4 , an alternative intrusive probe system 400according to one or more embodiments of the present invention isprovided. Probe system 400 includes a probe body 405 having an accessend 407 and a base end 409, the probe system 400 being configured to bepositioned such that the access end 407 is flush to a metal structure(e.g., a pipeline) and exposed to the liquids or gas in which atomichydrogen is produced. In this way, probe system 400 is configured tohave the same flush geometry as probe system 100. The access end 407 ofthe probe body 405 includes an exposed surface 410. Like exposed surface110, the exposed surface 410 is made of the same metal (e.g., steel)grade as the structure to be monitored, but has a HIC-resistantmicrostructure. In one or more embodiments, the access end 407 of theprobe 400 includes one or more O-rings 415. The O-ring(s) 415 isarranged about the outer surface of the probe body 405 to ensureliquid-tight geometry such that no liquid enters between the probe andstructure wall when the probe system 400 is installed.

In the illustrated embedment, the probe body 405 is formed of multipleparts that are coupled together to form the assembled probe body 405.More specifically, the probe body 405 includes an access end member 411and a filler rod 420 that is received within the access end member 411.The access end member 411 includes the exposed surface 410 along oneface thereof and a face opposite the exposed surface 410 includes arecessed portion 413 in which a first end (access end) of the filler rod420 is received. The recessed portion 413 formed in the access endmember 411 not only receives the first end of the filler rod 420 butalso serves to define a hydrogen collection cavity 425 defined betweenthe first end of the filler rod 420 and a floor of the hydrogencollection cavity 425. As shown, the recessed portion 413 can have astepped construction in which a landing defined therein provides asurface to which the first end of the filler rod 420 seats against. Theaccess end member 411 has a width greater than the filler rod 420 sincethe filler rod 420 is received internally therein.

The first end of the filler rod 420 is coupled to the access end member411 using any number of conventional techniques, including the use offasteners, bonding agents, adhesives, etc. In the illustratedembodiment, the first end of the filler rod 420 is coupled to the accessend member 411 by means of a weld as shown.

The filler rod 420 has a second end (base end) that is coupled to a cap430 (e.g., the same or similar to cap 135). An O-ring 437 can beprovided on the cap 430 to ensure a sealed fit between the cap 430 andanother abutting structure. In one or more embodiments, the filler rod420 is a metal rod having low or no hydrogen diffusivity. For example,the filler rod 420 can be made of an austenitic stainless steel or othermaterials disclosed herein.

As illustrated and unlike probe system 100, the filler rod 420 of probesystem 400 is not inserted into an opening formed in the probe body forcollecting recombined hydrogen gas but instead is inserted into therecessed portion of the access end member 411.

Instead, in one or more embodiments, the hydrogen collection cavity 425is an adjustable cavity 425 that mimics the creation of HIC voids. Morespecifically, the size (volume) of the cavity 425 can be tailored todifferent particular applications. The adjustability is at amanufacturing level in that the dimensions of the recessed portion canbe selected. In particular, the recessed cavity 425 can be formed at agreater depth to create a cavity of increased volume, while the recessedcavity 425 can be formed at a lesser depth to create a cavity of reducedvolume. In addition, the location of the landing that receives the firstend of the filler rod 420 can be varied so as to alter the volume of thecavity 425. The volume of the adjustable cavity 425 can thus be changedto simulate HIC arising at different thickness depths of the structure.As the volume of the adjustable cavity 425 is reduced, the probe system400 sensitivity to pressure build-ups increases. In certain embodiments,the volume of the adjustable cavity 425 is 2-3 cm³, 1-2 cm³ or 0.0314cm³ to 0.628 cm³ (with higher sensitivity being obtained with thesmaller cavity size). It will also be appreciated that for smaller sizedcavities, the higher the observed pressure rates and as a result, theuser will have to release the entrapped hydrogen gas in the annulus at agreater frequency. In other words, higher sensitivity results in morefrequent probe re-initialization.

In certain embodiments, the depth of the adjustable cavity 425 from theexposed surface 410 is less than 1 cm. In certain embodiments, the depthof the adjustable cavity 425 from the exposed surface 410 is less thanabout 0.5 cm.

As atomic hydrogen permeates the exposed surface 410, it passes throughthe access end member 411 into the adjustable cavity 425 where itrecombines into hydrogen gas in the adjustable cavity 425.

A conduit 435 is formed in the filler rod 420 and more particularly, theconduit 435 can be a longitudinal channel that extends along the lengthof the filler rod 420 and is open at both the first and second ends ofthe filler rod 420. The conduit 435 is also in fluid communication withthe adjustable cavity 425 as well as passing through the cap 430 so asto also be in fluid communication with a pressure measuring device 440.In other words, the conduit 435 can be thought of as a continuouschannel that passes through the probe body 405, cap 430 and at least aportion of the pressure measuring device 440. Like conduit 140, hydrogengas builds up in the adjustable cavity 425 and then passes to thepressure measuring device 440 by flowing through the conduit 435. Thepressure measuring device 440 can be any hydrogen pressure gauge ortransducer.

As with the previous embodiment, the access end member 411 is formed ofa material that is HIC resistant but permits passage (diffusion) of theatomic hydrogen to the hydrogen collection cavity 425 for recombinationtherein. In contrast, the filler rod 420, like filler rod 120, has lowor no hydrogen diffusivity properties and therefor, the hydrogen gasformed in the cavity 425 flows into the conduit 435 formed in the fillerrod 420 and does not diffuse into the filler rod 420 itself. As aresult, the formed hydrogen gas passes through probe 400 to the pressuremeasuring device 440 which is configured to measure the hydrogen gasbuildup as a result of atomic hydrogen permeation without significantloss to the surrounding structure.

With reference now to FIG. 5 , the installation of probe system 400 to astructure 505 is illustrated. The structure 505 can be a steel structurethat transports hydrocarbon products, such as a pipeline, pressurevessel, or other piping system transporting oil or gas. As in otherembodiments, the probe system 400 is coupled to an access fitting 510,which in turn is coupled to a coupling mount 515. As shown in FIG. 5 ,the access end member 411 of the probe system 400 is installed flush tothe inner wall of the coupling mount 515 and the exposed surface 410 isinstalled at least substantially flush to the inner surface of thestructure 505. In this arrangement, no hydrocarbon product within thestructure 505 can pass into the probe body 405 without passing throughthe exposed surface 410. An O-ring 415 is also preferably provided toform a liquid and gas tight seal between the probe 400 (i.e., the accessend member 411 thereof) and the coupling mount 515.

In the illustrated embodiment, the access fitting 510 can be an openended structure that has a central opening that receives the probe body.As shown, at least a portion of the central opening of the accessfitting 510 can be threaded (inner threads) and the cap 430 includesouter threads that mate with the inner threads to couple the probe 400to the access fitting 510. It will also be appreciated that the threadedarrangement allow adjustment of the probe 400 relative to the accessfitting 510 and in particular, the length of the probe 400 that extendsbeyond the distal end of the access fitting 510 can, in at least oneembodiment, be changed by the threaded arrangement between the twoparts. In another embodiment, there is a fixed position (orientation)between the probe 400 and the access fitting 510.

The probe systems as described herein can be implemented to provide awarning system as to possible HIC damage in sections of a structure. Ifthe hydrogen pressure increases beyond certain thresholds, thatindicates that an inspection (e.g., AUT) should be performed.Additionally, if the probe system indicates that a particular sectionhas increased chances of HIC or SWC cracking, then nearby sections ofthe structure may also be scheduled for inspection.

As such, provided herein are methods for warning for hydrogen inducedcracking. In this method, an intrusive probe system, such as probesystem 100 or probe system 400, is installed at a structure (e.g., steelpipeline, pressure vessel, piping system). Installation may be performedas described herein, such as by implementing coupling components such ascap 135, access fitting 210 and coupling mount 215. Next, atomichydrogen is produced by natural hydrocarbon processes within thestructure. The atomic hydrogen permeates the structure and an exposedsurface of the probe system (e.g., exposed surface 110, exposed surface410). The atomic hydrogen migrates to a cavity, where it recombines toform hydrogen gas. The cavity can be filled with a filler rod, or thecavity can be adjustable, as in adjustable cavity 425. The methodcontinues in that the pressure of the molecular hydrogen in the cavityis measured. Such measurements can be made by a pressure gauge,transducer, or other suitable hydrogen pressure device. If the pressureis higher than a particular threshold, a risk of HIC or SWC is present.The method then determines whether the measured pressure presents such arisk. There are multiple methods for making such determination. Forexample, a first method uses first principle calculations (See, Traidiaet al., IJHE 2012, which is incorporated by reference in its entirety. Asecond method uses an empirical correlation (developed in laboratoryexperiments) between pressure increase rate and measured crack growthrate (AUT).

If a risk of HIC or SWC is identified, the method can then alert theuser and schedules an AUT inspection at that area of the structure.Scheduling can be done automatically, such as by including acommunication device at the pressure device that transmits a signal to aprocessor upon measuring a particular pressure that the processorprocesses using suitable software to schedule an inspection.

In one embodiment, a device (PIG) that is used to carry out ILIinspection can pick up the measurements wirelessly from the probes(e.g., using Zigbee technology or related technology) while travelinginside the pipeline. As is known in the industry, PIGs are devices thatare in-line-inspection (ILI) tools used to detect the conditions of thepipeline, such as detecting and measuring corrosion. The measurementsfrom the probe can then be integrated directly into the ILI report andhelp interpret the results and make decision on whether or not to go fordig verification and/or repair. The probe of the present invention canthus include a communication module (e.g., wireless module or othercommunication protocol (e.g., Bluetooth) that communicates with a modulein the PIG to enable data transfer and communication therebetween.Communication between the PIG and the probe allows for data collectionby the PIG as it moves along the inner surface of the pipeline andtherefore a single report can be generated from the collected data.

The probe construction of the present invention was tested in a numberof experiments that monitored hydrogen pressure build-up in thecollection cavity of a period of time under conditions that simulated avoid in a pipeline that carries a fluid that induced sour corrosion onthe exposed surface. The results were that hydrogen pressure build-upwas observed in the simulated void over a period of days, therebyindicating that the probe construction of the present invention iseffective at monitoring and detecting conditions within the pipelinethat are indicative of HIC or SWC formation and growth in the pipeline.

FIGS. 1 through 5 are conceptual illustrations allowing for anexplanation of the present invention. Those of skill in the art shouldunderstand that various aspects of the embodiments of the presentinvention could be implemented in hardware, firmware, software, orcombinations thereof. In such embodiments, the various components and/orsteps would be implemented in hardware, firmware, and/or software toperform the functions of the present invention. That is, the same pieceof hardware, firmware, or module of software could perform one or moreof the illustrated blocks (e.g., components or steps).

In software embodiments, computer software (e.g., programs or otherinstructions) and/or data is stored on a machine-readable medium as partof a computer program product, and is loaded into a computer system orother device or machine via a removable storage drive, hard drive, orcommunications interface. Computer programs (also called computercontrol logic or computer readable program code) are stored in a mainand/or secondary memory, and implemented by one or more processors(controllers, or the like) to cause the one or more processors toperform the functions of the invention as described herein. In thisdocument, the terms “machine readable medium,” “computer program medium”and “computer usable medium” are used to generally refer to media suchas a random access memory (RAM); a read only memory (ROM); a removablestorage unit (e.g., a magnetic or optical disc, flash memory device, orthe like); a hard disk; or the like.

Notably, the figures and examples above are not meant to limit the scopeof the present invention to a single embodiment, as other embodimentsare possible by way of interchange of some or all of the described orillustrated elements. Moreover, where certain elements of the presentinvention can be partially or fully implemented using known components,only those portions of such known components that are necessary for anunderstanding of the present invention are described, and detaileddescriptions of other portions of such known components are omitted soas not to obscure the invention. In the present specification, anembodiment showing a singular component should not necessarily belimited to other embodiments including a plurality of the samecomponent, and vice-versa, unless explicitly stated otherwise herein.Moreover, applicants do not intend for any term in the specification orclaims to be ascribed an uncommon or special meaning unless explicitlyset forth as such. Further, the present invention encompasses presentand future known equivalents to the known components referred to hereinby way of illustration.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingknowledge within the skill of the relevant art(s) (including thecontents of the documents cited and incorporated by reference herein),readily modify and/or adapt for various applications such specificembodiments, without undue experimentation, without departing from thegeneral concept of the present invention. Such adaptations andmodifications are therefore intended to be within the meaning and rangeof equivalents of the disclosed embodiments, based on the teaching andguidance presented herein. It is to be understood that the phraseologyor terminology herein is for the purpose of description and not oflimitation, such that the terminology or phraseology of the presentspecification is to be interpreted by the skilled artisan in light ofthe teachings and guidance presented herein, in combination with theknowledge of one skilled in the relevant art(s).

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample, and not limitation. It would be apparent to one skilled in therelevant art(s) that various changes in form and detail could be madetherein without departing from the spirit and scope of the invention.Thus, the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. An intrusive probe system for flush insertioninto a metal asset comprising: a probe body having an access end memberthat is formed as a single solid body with an exposed surface configuredto be exposed to a corrodent located within the metal asset, the accessend member having a recessed portion formed opposite the exposedsurface, the recessed portion being defined by a first wall that isparallel to the exposed surface; an insert having an access end and abase end, the access end of the insert being disposed within therecessed portion such that the access end member surrounds and isdirectly coupled to the insert and is in contact with the access end ofthe insert, the access end of the insert being parallel to and spacedfrom the first wall of the recessed portion of the probe body so as todefine a collection cavity that is fluid-tight and configured to collectthe atomic hydrogen that permeates through the exposed surface of theaccess end member, wherein the insert includes a conduit that passestherethrough and is open at both the access end and the base end suchthat the conduit is in fluid communication with the collection cavity;and a pressure measuring device in fluid communication with the conduitof the insert for measuring a pressure of the gas generated by thediffused atomic hydrogen within the collection cavity.
 2. The probesystem of claim 1, wherein the recessed portion is formed along a faceof the access end portion opposite the exposed surface.
 3. The probesystem of claim 1, wherein the recessed portion has a steppedconstruction including a landing portion against which the access end ofthe insert sealingly seats.
 4. The probe system of claim 1, wherein thethrough hole is centrally located within the insert.
 5. The probe systemof claim 1, wherein the access end portion has a cylindrical shape. 6.The probe system of claim 1, further including a probe cap that iscoupled to the base end of the insert, the probe cap having a throughhole that axially aligns with the through hole formed in the insert todefine a conduit to the pressure measuring device.
 7. The probe systemof claim 1, wherein the insert comprises a cylindrical shaped fillerrod.
 8. The probe system of claim 1, further including an O-ring coupledto the access end portion adjacent to the exposed surface.
 9. The probesystem of claim 1, wherein the access end portion is formed of amaterial that permits diffusion of atomic hydrogen therethrough but hasan HIC resistant microstructure.
 10. The probe system of claim 1,wherein the insert is formed of an austenitic stainless steel material.11. The probe system of claim 1, further including a probe cap that iscoupled to the base end of the insert; an access fitting to which theprobe body is coupled; and a coupling mount that is configured to besealingly inserted into an access hole formed in the metal asset and towhich the access fitting is coupled.
 12. The probe system of claim 1,wherein the pressure measuring device is configured to send an alertonce the hydrogen build-up rate reaches a threshold value that isindicative of an increased chance of HIC or step-wise cracking (SWC) inthe metal asset.
 13. An intrusive metal probe system for flush insertioninto a metal asset comprising: an access end member that is formed as asingle solid body with an exposed surface configured to be exposed to acorrodent located within the metal asset, the access end member having arecessed portion formed opposite the exposed surface and being definedby a first wall that is parallel to the exposed surface; an insert beingat least partially disposed within the recessed portion of the accessend member such that the access end member surrounds and is directlycoupled to the insert and is in direct contact with the access end ofthe insert, the access end of the insert being parallel to and spacedfrom the first wall of the recessed portion of the access end member,the insert having a base end opposite the access end, the access end ofthe insert being disposed within the access end member so as to define acollection cavity that is fluid-tight and configured to collect theatomic hydrogen that permeates through the exposed surface of the accessend member, the collection cavity being formed between the access end ofthe insert and the first wall of the recessed portion of the access endmember, wherein the insert includes a conduit that passes therethroughand is open at both the access end and the base end such that theconduit is in fluid communication with the collection cavity; a cap, thebase end of the insert being received within a recessed portion formedin the cap such that the cap is in contact with and surrounds the baseend of the insert; and a pressure measuring device in fluidcommunication with the conduit of the insert for measuring a pressure ofthe gas generated by the diffused atomic hydrogen within the collectioncavity.
 14. The probe system of claim 13, wherein the conduit is formedcentrally within the insert.